The invention relates generally to hygroscopic wicks and, more particularly, to bicomponent fiber wicks that may be adapted for transmitting analyte fluids in assay devices.
Various assay devices are known for use in the home, office, clinic, hospital or doctor's surgery for providing an analytical result which is rapid and which requires a minimal degree of skill and involvement by the user. Examples of this are the test devices or assays for pregnancy and fertile period (ovulation). Typically in such devices the number of operations in getting the results should be minimized.
Typical assay devices comprise a housing, a reaction medium positioned in the housing, upon which the assay chemistry occurs, and a wick for collecting the liquid to be assayed and transferring it to the reaction medium. In general, the assay device should merely require that a collection portion of the device be contacted with a sample (e.g., a urine sample for pregnancy testing), and thereafter no further user actions are required. The sample is carried from the collection portion to the reaction medium via the wick. Observation of changes to the reaction medium or a substrate carrying the reaction medium provide an analytical result. Ideally, the analytical result should be observable within a matter of minutes following sampling.
The actual analytic techniques used to obtain the results typically determine the presence or absence of and/or quantify the amount of various analytes in tissues and fluids of organisms. Currently most diagnostic testing is done with blood, urine, fecal material, saliva, or tissue biopsy. Testing based on these materials, however, entails substantial invasion of privacy and poses a significant safety hazard (particularly with the testing of blood). Improved assay devices are required that allow for greater speed and control of the transport and analysis of the fluid sample. These devices will depend on improved wick materials and structures.